The present invention relates to agents, for detecting redox reactions, containing triaryl- and trihetarylmethane derivatives as redox indicators. These redox indicators can be employed to very good effect for the detection of hydrogen peroxide, particularly with the aid of peroxidases or peroxidatively-active substances
These redox indicators are furthermore suitable for the detection of peroxidases or peroxidatively-active compounds, where other peroxides may also be employed as oxidants.
Hydrogen peroxide is a reaction product which is produced during the enzymatically catalyzed oxidation of substrates such as, for example, glucose, cholesterol, uric acid, glycerol, glycerol phosphate, galactose, pyruvate or sarcosine by means of an appropriate oxidase such as glucose oxidase, cholesterol oxidase, uricase, glycerol oxidase, glycerol phosphate oxidase, galactose oxidase, pyruvate oxidase or sarcosine oxidase. The substrates mentioned belong to the group of analytical substances which play a role in clinical/chemical analysis. The hydrogen peroxide formed during the oxidase reaction can be detected polarographically, titrimetrically or potentiometrically. The colorimetric determination of hydrogen peroxide has considerably increased in importance due to the discovery of enzymes, such as peroxidase, catalase or haemoglobin, which convert hydrogen peroxide. Peroxidases, and also peroxidatively active substances (for example haemoglobin and methaemoglobin) catalyze the hydrogen peroxide-dependent oxidation of indicators such as guaiacol, dianisidine hydrochloride or ABTS into colored compounds. One of the best known detection reactions for hydrogen peroxide is the so-called "Trinder reaction" (Trinder, P. Ann. Clin Biochem., volume 6 (1969), pp. 24-27). 4-amino-antipyrine is oxidized by hydrogen peroxide in the presence of a peroxidase. The oxidation product is capable of coupling with a phenol or phenol derivative, a usually red quinone imine dyestuff being produced the concentration of which may be determined photometrically.